witness: lock order reversal: 1st 0xfffffd80084665d8 vmmaplk (&map->lock) 2nd 0xfffffd805676f3c8 inode (&ip->i_lock) lock order "&ip->i_lock"(rrwlock) -> "&map->lock"(rwlock) first seen at: #0 witness_checkorder+0x65e witness_lock_order_add sys/kern/subr_witness.c:2463 [inline] #0 witness_checkorder+0x65e sys/kern/subr_witness.c:880 #1 rw_enter_read+0x66 sys/kern/kern_rwlock.c:111 #2 uvmfault_lookup+0xd9 sys/uvm/uvm_fault.c:1495 #3 uvm_fault_check+0x3d sys/uvm/uvm_fault.c:513 #4 uvm_fault+0xdb sys/uvm/uvm_fault.c:694 #5 kpageflttrap+0x210 sys/arch/amd64/amd64/trap.c:267 #6 kerntrap+0xef sys/arch/amd64/amd64/trap.c:322 #7 alltraps_kern_meltdown+0x7b #8 copyout+0x53 #9 ffs_read+0x3e2 sys/ufs/ffs/ffs_vnops.c:258 #10 VOP_READ+0xbf sys/kern/vfs_vops.c:253 #11 vn_rdwr+0x10b #12 vmcmd_map_readvn+0xda sys/kern/exec_subr.c:246 #13 exec_process_vmcmds+0xb2 sys/kern/exec_subr.c:143 #14 sys_execve+0x9ff sys/kern/kern_exec.c:461 #15 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #15 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 #16 Xsyscall+0x128 lock order "&map->lock"(rwlock) -> "&ip->i_lock"(rrwlock) first seen at: #0 witness_checkorder+0x65e witness_lock_order_add sys/kern/subr_witness.c:2463 [inline] #0 witness_checkorder+0x65e sys/kern/subr_witness.c:880 #1 rw_enter+0xd4 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 #4 vn_lock+0x6c sys/kern/vfs_vnops.c:575 #5 uvn_io+0x2b5 sys/uvm/uvm_vnode.c:1201 #6 uvn_get+0x236 sys/uvm/uvm_vnode.c:1061 #7 uvm_fault+0xa41 sys/uvm/uvm_fault.c:1073 #8 uvm_fault_wire+0x63 sys/uvm/uvm_fault.c:1342 #9 uvm_map_pageable_wire+0x30d sys/uvm/uvm_map.c:2367 #10 sys_mlock+0x180 sys/uvm/uvm_mmap.c:772 #11 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #11 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 #12 Xsyscall+0x128 Stopped at db_enter+0x18: addq $0x8,%rsp ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic the kernel did not panic ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 witness_checkorder(fffffd805676f3c8,9,0) at witness_checkorder+0xf5a witness_debugger sys/kern/subr_witness.c:2490 [inline] witness_checkorder(fffffd805676f3c8,9,0) at witness_checkorder+0xf5a sys/kern/subr_witness.c:1087 rw_enter(fffffd805676f3b8,81) at rw_enter+0xd4 rrw_enter(fffffd805676f3b8,81) at rrw_enter+0x88 sys/kern/kern_rwlock.c:462 VOP_LOCK(fffffd805e9d34e8,81) at VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 vn_lock(fffffd805e9d34e8,81) at vn_lock+0x6c sys/kern/vfs_vnops.c:575 uvn_io(fffffd8057a80498,ffff8000212d80f8,1,2,0) at uvn_io+0x2b5 sys/uvm/uvm_vnode.c:1201 uvn_get(fffffd8057a80498,5000,ffff8000212d8358,ffff8000212d82f4,0,0) at uvn_get+0x236 sys/uvm/uvm_vnode.c:1061 uvm_fault(fffffd80084665c0,20005000,2,2) at uvm_fault+0xa41 sys/uvm/uvm_fault.c:1073 uvm_fault_wire(fffffd80084665c0,20005000,20006000,2) at uvm_fault_wire+0x63 sys/uvm/uvm_fault.c:1342 uvm_map_pageable_wire(fffffd80084665c0,fffffd8060c7b778,fffffd8060c7bcb8,3aa,ffffffff8134b61e,0) at uvm_map_pageable_wire+0x30d sys/uvm/uvm_map.c:2367 sys_mlock(ffff8000ffff47c8,ffff8000212d8538,ffff8000212d8580) at sys_mlock+0x180 sys/uvm/uvm_mmap.c:772 syscall(ffff8000212d8600) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000212d8600) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x379a42b3090, count: -14 ddb{0}> show registers rdi 0x3 rsi 0x40000 acpi_pdirpa+0x2be68 rbp 0xffff8000212d7d50 rbx 0x3 rdx 0xffff800000af6480 rcx 0x3 rax 0x3ffff acpi_pdirpa+0x2be67 r8 0xffffffff813492c3 witness_checkorder+0xf33 r9 0x5 r10 0x530c43961d7dd7d5 r11 0xa0eb7295c4e2c069 r12 0xffffffff82846d90 w_lodata+0x54430 r13 0 r14 0xffffffff82831050 w_lodata+0x3e6f0 r15 0xfffffd8002c9d500 rip 0xffffffff81a69268 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000212d7d40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=74833 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=72, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff5498,0xffffffff828a2128 process=0xffff8000ffff39e0 user=0xffff8000212d3000, vmspace=0xfffffd80084665c0 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 32346 366900 5314 32767 7 0x10 syz-executor.0 *32346 74833 5314 32767 7 0x4000010 syz-executor.0 8658 365976 60697 32767 3 0x10 biowait syz-executor.1 5314 141433 5143 32767 3 0x90 nanosleep syz-executor.0 60697 75572 73684 0 3 0x82 wait syz-executor.1 5143 411725 73684 0 3 0x82 wait syz-executor.0 73684 261506 39490 0 3 0x82 thrsleep syz-fuzzer 73684 275243 39490 0 3 0x4000082 nanosleep syz-fuzzer 73684 115738 39490 0 3 0x4000082 thrsleep syz-fuzzer 73684 31622 39490 0 3 0x4000082 kqread syz-fuzzer 73684 339608 39490 0 3 0x4000082 thrsleep syz-fuzzer 73684 280513 39490 0 3 0x4000082 thrsleep syz-fuzzer 73684 250755 39490 0 3 0x4000082 nanosleep syz-fuzzer 73684 502948 39490 0 3 0x4000082 thrsleep syz-fuzzer 39490 377316 43763 0 3 0x10008a pause ksh 43763 141984 79420 0 3 0x92 select sshd 8468 27742 1 0 3 0x100083 ttyin getty 79420 517216 1 0 3 0x80 select sshd 95201 93914 29866 73 3 0x100090 kqread syslogd 29866 83308 1 0 3 0x100082 netio syslogd 76061 514007 1 77 3 0x100090 poll dhclient 17443 70066 1 0 3 0x80 poll dhclient 59426 112649 0 0 3 0x14200 bored smr 18512 118764 0 0 3 0x14200 pgzero zerothread 81785 68340 0 0 3 0x14200 aiodoned aiodoned 28915 348655 0 0 3 0x14200 syncer update 2147 249058 0 0 3 0x14200 cleaner cleaner 19284 246919 0 0 3 0x14200 reaper reaper 64692 177728 0 0 3 0x14200 pgdaemon pagedaemon 70334 497107 0 0 3 0x14200 bored crynlk 4497 230141 0 0 3 0x14200 bored crypto 27617 190089 0 0 3 0x14200 bored viomb 93433 330955 0 0 3 0x40014200 acpi0 acpi0 75804 139011 0 0 3 0x40014200 idle1 62806 357271 0 0 3 0x14200 bored softnet 16031 82989 0 0 3 0x14200 bored systqmp 79558 163312 0 0 3 0x14200 bored systq 98579 268327 0 0 3 0x40014200 bored softclock 24513 433963 0 0 3 0x40014200 idle0 1 374327 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 32346 (syz-executor.0) thread 0xffff8000ffff47c8 (74833) shared rwlock vmmaplk r = 0 (0xfffffd80084665d8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 rw_enter+0x446 sys/kern/kern_rwlock.c:311 #2 vm_map_lock_ln+0xda sys/uvm/uvm_map.c:5463 #3 uvm_map_pageable+0x120 sys/uvm/uvm_map.c:2463 #4 sys_mlock+0x180 sys/uvm/uvm_mmap.c:772 #5 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #5 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 #6 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828a2e98) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 syscall+0x3fd mi_syscall sys/sys/syscall_mi.h:93 [inline] #1 syscall+0x3fd sys/arch/amd64/amd64/trap.c:591 #2 Xsyscall+0x128 Process 8658 (syz-executor.1) thread 0xffff8000ffff4a58 (365976) exclusive rrwlock inode r = 0 (0xfffffd805676f2b8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 rw_enter+0x446 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 #4 vn_lock+0x6c sys/kern/vfs_vnops.c:575 #5 vget+0x1c6 sys/kern/vfs_subr.c:671 #6 ufs_ihashget+0x121 sys/ufs/ufs/ufs_ihash.c:119 #7 ffs_vget+0x6b sys/ufs/ffs/ffs_vfsops.c:1321 #8 ufs_lookup+0x151d sys/ufs/ufs/ufs_lookup.c:487 #9 VOP_LOOKUP+0x5b sys/kern/vfs_vops.c:90 #10 vfs_lookup+0x708 sys/kern/vfs_lookup.c:568 #11 namei+0x5f7 sys/kern/vfs_lookup.c:249 #12 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1848 #13 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #13 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 #14 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd806bac0928) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 rw_enter+0x446 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 #4 vn_lock+0x6c sys/kern/vfs_vnops.c:575 #5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419 #6 namei+0x5f7 sys/kern/vfs_lookup.c:249 #7 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1848 #8 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 #9 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9477 6349K 6349K 78643K 10568 0 pcb 13 8K 8K 78643K 13 0 rtable 107 3K 3K 78643K 193 0 ifaddr 39 10K 10K 78643K 39 0 sysctl 2 0K 0K 78643K 2 0 counters 43 33K 33K 78643K 43 0 ioctlops 0 0K 2K 78643K 3696 0 iov 0 0K 12K 78643K 4854 0 mount 1 1K 1K 78643K 1 0 vnodes 1217 77K 77K 78643K 1230 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 84 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 3312 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1825 197K 290K 78643K 13109 0 file desc 7 21K 33K 78643K 143679 0 sigio 0 0K 0K 78643K 21 0 proc 48 50K 70K 78643K 441 0 subproc 34 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 2 0 in_multi 33 2K 2K 78643K 33 0 ether_multi 1 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 43 201K 201K 78643K 43 0 exec 0 0K 2K 78643K 989 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 606 76K 76K 78643K 327337 0 UVM aobj 131 4K 4K 78643K 133 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 47047 0 NDP 5 0K 0K 78643K 9 0 temp 102 3965K 4029K 78643K 289315 0 kqueue 3 4K 8K 78643K 186 0 SYN cache 2 16K 16K 78643K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 120 36 0 34 1 0 1 1 0 8 0 rtentry 112 46 0 1 2 0 2 2 0 8 0 unpcb 120 60407 0 60399 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 413 0 413 4 4 0 3 0 8 0 tcpcb 736 6869 0 6857 111 109 2 8 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 2 0 2 1 1 0 1 0 8 0 inpcb 296 65700 0 65692 38 36 2 2 0 8 1 ip6q 72 1 0 1 1 1 0 1 0 8 0 ip6af 40 2 0 2 1 1 0 1 0 8 0 nd6 48 7 0 0 1 0 1 1 0 8 0 kcovpl 48 2 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 190 0 0 12 0 12 12 0 8 0 art_table 32 191 0 0 2 0 2 2 0 8 0 art_node 16 45 0 4 1 0 1 1 0 8 0 sysvmsgpl 40 12 0 3 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 3308 0 3298 1 0 1 1 0 8 0 shmpl 112 130 0 2 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 146980 0 145582 88 0 88 88 0 8 0 ffsino 272 146980 0 145582 94 0 94 94 0 8 0 nchpl 144 328519 0 326922 60 0 60 60 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 208 5926 0 0 312 0 312 312 0 8 0 namei 1024 677927 0 677927 4 3 1 1 0 8 1 percpumem 16 32 0 0 1 0 1 1 0 8 0 scxspl 216 878385 0 878384 14 13 1 8 0 8 0 plimitpl 152 152 0 143 1 0 1 1 0 8 0 sigapl 424 143867 0 143835 4 0 4 4 0 8 0 futexpl 56 919722 0 919722 3 2 1 1 0 8 1 knotepl 112 242 0 222 1 0 1 1 0 8 0 kqueuepl 152 146800 0 146774 14 12 2 2 0 8 0 pipepl 304 4228 0 4217 42 41 1 2 0 8 0 fdescpl 496 143851 0 143835 3 0 3 3 0 8 0 filepl 152 504007 0 503905 21 16 5 5 0 8 1 lockfpl 104 4282 0 4280 1 0 1 1 0 8 0 lockfspl 48 2103 0 2101 1 0 1 1 0 8 0 sessionpl 144 17 0 7 1 0 1 1 0 8 0 pgrppl 48 28 0 18 1 0 1 1 0 8 0 ucredpl 96 26142 0 26133 1 0 1 1 0 8 0 zombiepl 144 143835 0 143835 2 1 1 1 0 8 1 processpl 1056 143867 0 143835 5 2 3 3 0 8 0 procpl 656 294375 0 294335 6 2 4 5 0 8 0 sockpl 400 126689 0 126671 48 45 3 4 0 8 0 mcl64k 65536 31 0 0 4 1 3 3 0 8 0 mcl16k 16384 24 0 0 3 0 3 3 0 8 0 mcl12k 12288 81 0 0 3 1 2 2 0 8 0 mcl9k 9216 17 0 0 2 0 2 2 0 8 0 mcl8k 8192 38 0 0 3 1 2 3 0 8 0 mcl4k 4096 65 0 0 4 1 3 3 0 8 0 mcl2k2 2112 17 0 0 2 0 2 2 0 8 0 mcl2k 2048 754 0 0 66 51 15 66 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 2277 0 0 35 3 32 35 0 8 0 bufpl 280 150111 0 143864 447 0 447 447 0 8 0 anonpl 16 8493133 0 8411555 393 13 380 391 0 124 0 amapchunkpl 152 451048 0 447717 158 28 130 150 0 158 0 amappl16 192 241391 0 239106 117 2 115 117 0 8 0 amappl15 184 3 0 2 1 0 1 1 0 8 0 amappl14 176 23 0 18 1 0 1 1 0 8 0 amappl13 168 71348 0 71346 1 0 1 1 0 8 0 amappl12 160 72356 0 72349 1 0 1 1 0 8 0 amappl11 152 47 0 36 1 0 1 1 0 8 0 amappl10 144 6 0 3 1 0 1 1 0 8 0 amappl9 136 254 0 253 2 1 1 1 0 8 0 amappl8 128 258 0 164 4 0 4 4 0 8 0 amappl7 120 218 0 210 1 0 1 1 0 8 0 amappl6 112 67 0 54 1 0 1 1 0 8 0 amappl5 104 1840 0 1824 1 0 1 1 0 8 0 amappl4 96 72711 0 72684 1 0 1 1 0 8 0 amappl3 88 150493 0 150478 1 0 1 1 0 8 0 amappl2 80 1075988 0 1075921 2 0 2 2 0 8 0 amappl1 72 4415965 0 4415481 40 30 10 18 0 8 0 amappl 80 295054 0 294556 11 0 11 11 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 64 132 0 2 3 0 3 3 0 8 0 uaddrrnd 24 143851 0 143835 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 143851 0 143835 1 0 1 1 0 8 0 vmmpekpl 168 615290 0 615262 2 0 2 2 0 8 0 vmmpepl 168 18637410 0 18633312 384 199 185 287 0 357 0 vmsppl 368 143850 0 143835 2 0 2 2 0 8 0 pdppl 4096 287709 0 287670 6 0 6 6 0 8 0 pvpl 32 33498728 0 33413920 807 23 784 807 0 265 0 pmappl 232 143850 0 143835 2 1 1 2 0 8 0 extentpl 40 57 0 39 1 0 1 1 0 8 0 phpool 112 487 0 216 10 0 10 10 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 witness_checkorder(fffffd805676f3c8,9,0) at witness_checkorder+0xf5a witness_debugger sys/kern/subr_witness.c:2490 [inline] witness_checkorder(fffffd805676f3c8,9,0) at witness_checkorder+0xf5a sys/kern/subr_witness.c:1087 rw_enter(fffffd805676f3b8,81) at rw_enter+0xd4 rrw_enter(fffffd805676f3b8,81) at rrw_enter+0x88 sys/kern/kern_rwlock.c:462 VOP_LOCK(fffffd805e9d34e8,81) at VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 vn_lock(fffffd805e9d34e8,81) at vn_lock+0x6c sys/kern/vfs_vnops.c:575 uvn_io(fffffd8057a80498,ffff8000212d80f8,1,2,0) at uvn_io+0x2b5 sys/uvm/uvm_vnode.c:1201 uvn_get(fffffd8057a80498,5000,ffff8000212d8358,ffff8000212d82f4,0,0) at uvn_get+0x236 sys/uvm/uvm_vnode.c:1061 uvm_fault(fffffd80084665c0,20005000,2,2) at uvm_fault+0xa41 sys/uvm/uvm_fault.c:1073 uvm_fault_wire(fffffd80084665c0,20005000,20006000,2) at uvm_fault_wire+0x63 sys/uvm/uvm_fault.c:1342 uvm_map_pageable_wire(fffffd80084665c0,fffffd8060c7b778,fffffd8060c7bcb8,3aa,ffffffff8134b61e,0) at uvm_map_pageable_wire+0x30d sys/uvm/uvm_map.c:2367 sys_mlock(ffff8000ffff47c8,ffff8000212d8538,ffff8000212d8580) at sys_mlock+0x180 sys/uvm/uvm_mmap.c:772 syscall(ffff8000212d8600) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000212d8600) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:591 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x379a42b3090, count: -14 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff800020d70ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x7 sys/dev/kcov.c:139 upageflttrap(ffff8000234ec560,379b9ccd500) at upageflttrap+0x77 sys/arch/amd64/amd64/trap.c:180 usertrap(ffff8000234ec560) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:407 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffefd20, count: -7